Idiopathic dilated cardiomyopathy: Advances in aetiology, pathogenesis and management

In most cases of dilated cardiomyopathy in the dog (and in man) the aetiology is unknown; these cases are designated idiopathic. Recent advances, particularly in the field of molecular biology, are providing a better understanding of the natural history of the disease and are shedding light on possible primary causes of dilated cardiomyopathy as well as some of the factors which may be responsible for the progressive nature of the disease process. Armed with this information, more specific therapeutic regimes can be developed with the aim of stopping or reversing myocardial damage. The use of skeletal muscle to assist the failing myocardium may offer a practical means of improving a patient's cardiovascular status, particularly in cases where conventional medical therapy is failing to control the progression of the clinical signs.     

Further data to the aetiology, pathogenesis and therapy of infectious bovine keratoconjunctivitis

Out of a total of 224 bovine eye secretions, 126 Moraxella bovis and 64 Neisseria ovis strains were isolated. The pathogenesis and histological lesions caused by Neisseria ovis have been studied on the eyes of three calves naturally affected with IBK, using electron microscopy.

Neisseria ovis caused in 1–12 weeks old calves acute, transient and mostly benign serous conjunctivitis with only slight affection of the cornea. More rarely erosions and even ulceration of the cornea have been observed.

Moraxella bovis and Neisseria ovis strains proved nearly unanimously sensitive in vitro to chloramphenicol, neomycin, oxytetracyclin, nitrofurantoin, erythromycin and cefoperazone. Other antibiotics and chemotherapeutics inhibited the growth of these agents only partly or were ineffective.

Experimental therapy has been carried out using a single i.m. injection of Terramycin/LA inj. (Pfizer) in a dose of 20 mg/kg body mass, repeated if necessary after 72–96 h. This formulation proved more effective and practical than treatments used earlier.     

Bovine pododermatitis aseptica diffusa (laminitis) aetiology,pathogenesis, treatment and control

Pododermatitis aseptica diffusa (laminitis) is a major cause of lameness and discomfort to cattle with resultant economic losses. The disease is a result of multifactorial aetiology most of which is not clearly understood. Feeding readily fermentable carbohydrates to unaccustomed cattle predisposes to the disease. Histamine, lactic acid and endotoxins are believed to be involved. Systemic acidosis, histaminosis and endotoxaemia are thought to produce the pathophysiological characteristics of laminitis. The diagnosis is primarily based on the observation of symmetrical and bilateral lesions in hooves and characteristic lameness affecting all feet. Gross lesions include concavity of the dorsal wall, discolorations in the sole and rotation of the pedal bone. Degenerative changes and arteriosclerosis are constant histological findings in the corium, with chronic thrombi and chronic granulation tissue. The disease may be treated conservatively and by application of cyclooxygenase inhibiting non-steroidal anti-inflammatory drugs and prevented or controlled by proper feeding and management practices.     

Evaluation of the pathology,pathogenesis and aetiology of auricular elephantiasis in slaughter pigs

Ears from slaughter pigs with auricular elephantiasis (n = 24) and the corresponding lymph nodes (lnn.) (n = 26) were grossly, histopathologically and microbiologically examined. Immunostaining for IgM, IgG, Cd3epsilon and bacterial antigens of Arcanobacterium pyogenes and Staphylococcus aureus was performed by indirect enzyme-based techniques. Ears were variably thickened depending on the sampled area (basis, centre and apex). However, at all locations the thickness, the length from basis to apex and the weigh of whole ears with elephantiasis were significantly increased (P < 0.01). The corresponding lnn., that is, ln. parotideus superficialis and profundus, had also increased significantly (P < 0.01) in volume. Histopathologically, lesions of the ears and the corresponding lnn. revealed changes characterized by diffuse fibrosis intermingled with multiple pyogranulomatous foci containing asteroid bodies. In the majority of lesions, four distinct zones due to different cellular infiltrates encircled the central core of the asteroid bodies. In several lesions, the pyogranulomatous foci were contained within the lymph vessels. Immunohistochemically, only the bacterial antigen of S. aureus was detected within the cytoplasm of the macrophages and/or in the asteroid bodies of the ears (41.5%) and in the regional lnn. (30.8%). An abundant number of IgM, IgG and CD3epsilon-positive cells were present in all the pyogranulomatous lesions, whereas a positive IgG-staining was observed only in a single asteroid body. Thus, porcine auricular elephantiasis is a chronic pyogranulomatous inflammation that is frequently positive for S. aureus and is lymphogenically spread. Therefore, the lesions of the ears with auricular elephantiasis and the corresponding lnn. should be termed auricular botryomycosis and botryomycotic lymphadenitis, respectively. Moreover, as the disease is observed frequently in slaughter pigs it must also be considered according to the welfare of the animals and in relation to post-mortem meat inspection.     

Pyelonephritis in slaughter pigs and sows: Morphological characterization and aspects of pathogenesis and aetiology

Background

Pyelonephritis is a serious disease in pig production that needs to be further studied. The purpose of this study was to describe the morphology, investigate the pathogenesis, and evaluate the aetiological role of Escherichia coli in pyelonephritis in slaughtered pigs by concurrent bacteriological, gross and histopathological examinations.

Methods

From Danish abattoirs, kidneys and corresponding lymph nodes from 22 slaughtered finishing pigs and 26 slaughtered sows with pyelonephritis were collected and evaluated by bacteriology and pathology. Based on gross lesions, each kidney (lesion) was grouped as acute, chronic, chronic active, or normal and their histological inflammatory stage was determined as normal (0), acute (1), sub-acute (2), chronic active (3), or chronic (4). Immunohistochemical identification of neutrophils, macrophages, T-lymphocytes, B-lymphocytes, plasma cells, E. coli and Tamm-Horsfall protein (THP) in renal sections was performed. The number of E. coli and the proportion of immunohistochemically visualized leukocytes out of the total number of infiltrating leukocytes were scored semi-quantitatively.

Results

Lesions in finishing pigs and sows were similar. Macroscopically, multiple unevenly distributed foci of inflammation mostly affecting the renal poles were observed. Histologically, tubulointerstitial infiltration with neutrophils and mononuclear cells and tubular destruction was the main findings. The significant highest scores of L1 antigen⁺ neutrophils were in inflammatory stage 1 while the significant highest scores of CD79αcy⁺ B-lymphocytes, IgG⁺ and IgA⁺ plasma cells were in stage 3 or 4. Neutrophils were the dominant leukocytes in stage 1 while CD3ε⁺ T-lymphocytes dominated in stage 2, 3 and 4. Interstitially THP was seen in 82% and 98% of kidneys with pyelonephritis from finishing pigs and sows, respectively. E. coli was demonstrated in monoculture and/or identified by immunohistochemistry in relation to inflammation in four kidneys from finishing pigs and in 34 kidneys from sows.

Conclusions

E. coli played a significant role in the aetiology of pyelonephritis. Neutrophils were involved in the first line of defence. CD3ε⁺ T-lymphocytes were involved in both the acute and chronic inflammatory response while a humoral immune response was most pronounced in later inflammatory stages. The observed renal lesions correspond with an ascending bacterial infection with presence of intra-renal reflux.     

Cystic ovarian disease in dairy cattle: aetiology, pathogenesis, and risk factors

Cystic ovarian disease (COD) is an important ovarian dysfunction in dairy cattle, especially during the early postpartum period. The endocrinology and the symptoms of this disorder vary widely due to the many different forms of cysts that exist. For these reasons, there is currently no clear and unambiguous definition of COD. When ovulation does not occur, a follicle may evolve into an ovarian cyst. Folliculogenesis and ovulation are regulated by the hypothalamic-pituitary-gonadal axis. A dysfunction can occur at different levels of this neuroendocrine system, causing COD. The primary factor is thought to be a deficient luteinizing hormone surge prior to ovulation. What causes this alteration is not yet known. Many factors increase the incidence of COD and are involved in the very complex pathogenesis of this disease.     

Canine ureteral ectopia--a review. 1. Embryology and aetiology

The embryological reasons for the possible appearance of ectopic ureters in dogs are discussed. Résumé. On discute des raisons embryologiques pour l'apparition possible d'uretères ecto-piques chez les cheins. Zusammenfassung. Die erabryologischen Griinde fur das mǒgliche Erscheinen von ektopischen Ureteren in Hunden wurde diskutiert.     

Periodontal disease. Etiology and pathogenesis

Periodontal disease is the number-one cause of the early loss of teeth in dogs and cats. Some of the factors in the adult animal that play a major role in the development of periodontal diseases are discussed in this article, including overcrowding, malocclusions, diet, developmental defects, and metabolic and systemic disease.